Multiple on-line sensor systems and methods
First Claim
1. A device that automatically controls selection of signal inputs from first and second probes positioned to simultaneously sense atmosphere having an oxygen content contained within a heat treating furnace, the device comprisingan input element for electrical connection to the first and second probes to receive input signals independently from each probe relating to oxygen content of the furnace atmosphere,a processing element means electrically connected to the input element for comparing the received input signal from the first probe to the received input signal from the second probe and for selecting the first probe and not the second probe as a control probe when the comparison meets a first criteria and for selecting the second probe and not the first probe as a control probe when the comparison meets a second criteria different than the first criteria, andan output element electrically connected to the input element and responsive to the processing element to transmit as control outputs the received input signals from only the one selected control probe.
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Accused Products
Abstract
A control device and associated methodology select from at least two on-line sensors to assure an accurate and reliable feedback input to control the heat treating conditions within a furnace. The device and methodology also serve to provide an "alert" or "early warning" of gradual degradation of sensor performance, before ongoing heat treating operations are adversely affected.
62 Citations
30 Claims
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1. A device that automatically controls selection of signal inputs from first and second probes positioned to simultaneously sense atmosphere having an oxygen content contained within a heat treating furnace, the device comprising
an input element for electrical connection to the first and second probes to receive input signals independently from each probe relating to oxygen content of the furnace atmosphere, a processing element means electrically connected to the input element for comparing the received input signal from the first probe to the received input signal from the second probe and for selecting the first probe and not the second probe as a control probe when the comparison meets a first criteria and for selecting the second probe and not the first probe as a control probe when the comparison meets a second criteria different than the first criteria, and an output element electrically connected to the input element and responsive to the processing element to transmit as control outputs the received input signals from only the one selected control probe.
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6. A device that monitors signal inputs from first and second probes positioned to simultaneously sense atmosphere contained within a heat treating furnace, the device comprising
an input element for electrical connection to the probes to receive input signals independently from each probe related to the atmosphere contained within the furnace, and a processing element means electrically connected to the input element for comparing the received input signal from the first probe to the received input signal from the second probe and for generating a first diagnostic output for the first and not the second probe when the comparison fails to meet a first criteria and for generating a second diagnostic output for the second and not the first probe when the comparison fails to meet a second criteria different than the first criteria.
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13. A device that automatically controls selection of signal inputs from first and second probes positioned to simultaneously sense atmosphere contained within a heat treating furnace, the device comprising
an input element for electrical connection to the probes to receive input signals independently from each probe related to the atmosphere contained within the furnace, a processing element means electrically connected to the input element for comparing the received input signal from the first probe to the received input signal from the second probe and for selecting one probe as a control probe and one probe as a standby probe based upon the comparison, an output element electrically connected to the input element and responsive to the processing element to transmit as control outputs the received input signals from only the one selected control probe, and the processing element means also serving, after selection of the control probe, to compare the received input signals of the selected standby probe and the selected control probe to generate a diagnostic output when the comparison fails to meet set criteria.
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20. A heat treating system comprising
a heat treating furnace, a source for generating heat treating atmosphere having an oxygen content and supplying the atmosphere to the furnace, multiple probes positioned to simultaneously sense the atmosphere supplied to the furnace, each probe independently generating an input signal having a magnitude which is related to the oxygen content of the atmosphere, an interface for controlling selection of the input signals from the multiple probes, the interface comprising an input element electrically coupled to the probes to receive input signals independently from each probe, a processing element means electrically connected to the input element for comparing the magnitude of the received input signals from each probe and for selecting one probe as a control probe based upon the comparison, and an output element electrically connected to the input element and responsive to the processing element to transmit as control outputs the received input signals from only the one selected control probe, and a controller electrically coupled to the source and to the interface for receiving the control outputs to create and maintain the atmosphere.
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25. A heat treating system comprising
a heat treating furnace, a source for generating heat treating atmosphere and supplying the atmosphere to the furnace, multiple probes positioned to simultaneously sense the atmosphere supplied to the furnace, each probe independently generating an input signal relating to the atmosphere, an interface for monitoring the input signals from the multiple probes, the interface comprising an input element electrically coupled to the probes to receive input signals independently from each probe, a processing element means electrically connected to the input element for comparing the received input signals from each probe and for generating a diagnostic output when the comparison fails to meet set criteria.
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29. A method for selecting signal inputs from at least two probes positioned to simultaneously sense atmosphere of a heat treating furnace, the atmosphere having oxygen content, the method comprising the steps of
receiving input signals independently from each probe, the input signals having magnitude, the magnitude of the input signals being related to oxygen content of the atmosphere, periodically sampling the magnitudes of the received input signals from each probe, comparing the sampled magnitudes, selecting one of the probes as a control probe based, at least in part, upon the comparison of the sampled magnitudes, and transmitting as a control output the received input signals from only the one selected control probe.
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30. A method for monitoring performance at least two probes positioned to simultaneously sense atmosphere of a heat treating furnace comprising the steps of
receiving input signals independently from each probe, the input signals having magnitude, the input signals being related to the atmosphere in the furnace, periodically sampling the magnitudes of the received input signals from each probe while, performing a first comparison of the sampled magnitudes to select one of the probes as a control probe and one of the probes as a standby probe based, at least in part, upon the first comparison of the sampled magnitudes, and performing after the first comparison a second comparison of the sampled magnitudes to generate a diagnostic output when the second comparison fails to meet set criteria.
Specification